Among Leon Cooperman's many contributions to investing knowledge was a perfect 10-for-10 slate in ideas at the 2012 Delivering Alpha conference.

With that enviable record to live up to, Cooperman decided to take another shot this year, though not without warning.

In 2012, he saw a stock market that had much stronger prospects than now, so he believes investors had better brace themselves for a different environment.

"I wouldn't be surprised personally if the market got into corrective mode or we went sideways for a while," he said at the conference presented by CNBC and Institutional Investor. "I've got a sense that I could be wrong because (Fed Chairman Ben) Bernanke is getting his way. Everyone is moving out to varying degrees on the risk curve."

Using corporate profits as a gauge, Cooperman said this year's forecast 4 percent earnings growth on the S&P 500 does not justify the 18 percent move higher in the index.

"What bothers me is...what the wise man does in the beginning, the fool does in the end," he said.